Search results for "Steiner"
showing 10 items of 47 documents
Triple planes with $p_g=q=0$
2019
We show that general triple planes with p_g=q=0 belong to at most 12 families, that we call surfaces of type I,..., XII, and we prove that the corresponding Tschirnhausen bundle is direct sum of two line bundles in cases I, II, III, whereas is a rank 2 Steiner bundle in the remaining cases. We also provide existence results and explicit constructions for surfaces of type I,..., VII, recovering all classical examples and discovering several new ones. In particular, triple planes of type VII provide counterexamples to a wrong claim made in 1942 by Bronowski.
Modulation of immune responses of Rhynchophorus ferrugineus (Insecta: Coleoptera) induced by the entomopathogenic nematode Steinernema carpocapsae (N…
2014
Aim of this study was to investigate relationships between the red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier) and the entomopathogenic nematode Steinernema carpocapsae (EPN); particularly, the work was focused on the immune response of the insect host in naive larvae and after infection with the EPN. Two main immunological processes have been addressed: the activity and modulation of host prophenoloxidase-phenoloxidase (proPO) system, involved in melanization of not-self and hemocytes recognition processes responsible for not-self encapsulation. Moreover, immune depressive and immune evasive strategies of the parasite have been investigated. Our results suggest that RPW possess a…
Entomopatogēno nematožu Steinernema feltiae (Filipiev 1934) sastopamības novērtējuma aprobācija pēc Galleria mellonella metodes, to populācijas izmai…
2020
Darbā kalibrēta vienkārša, kvantitatīva metode entomopatogēno nematožu Steinernema feltiae (Filipiev, 1934) sastopamības novērtēšanai izmantojot Galleria mellonella (Linnaeus, 1758) kāpurus kā ēsmu. G. mellonella ēsmas tests tika kalibrēts divu dažāda vecuma sterilizētas kokosa šķiedras substrātā, kur tika konstatēta būtiska korelācija starp S. feltiae indivīdu blīvumu un G. mellonella mirstību 48h laikā gan svaigā (p<0.01, r=0.86, n=25), gan trīs gadus lietotajā (p<0.01, r=0.85, n=25) substrātā. Piecu nedēļu laikā dažāda vecuma rožu stādījumos ievāktos paraugos reģistrētas atšķirības pētījumā iesaistīto taksonu sastāvā, konstatēta S. feltiae telpiskās izplatības heterogenitāte, ilgstoša sa…
Concise and modular synthesis of regioisomeric haptens for the production of high-affinity and stereoselective antibodies to the strobilurin azoxystr…
2011
The immune response to regioisomeric haptens of azoxystrobin with varied derivatization sites was studied. Based on the Sonogashira and Suzuki-Miyaura couplings and following a straightforward modular design, we have synthesized four haptens with the same linker anchored through C-C bonds and located at different sites of the molecule. The most stereoselective antibodies were produced from immunogens with the spacer arm at a distal position from the β-methoxyacrylate moiety characteristic of strobilurins. Moreover, we observed that assay cross-reactivity was reliant on the functionalization site of the competitor derivative. Finally, the antibody binding site was explored using synthetic ch…
Steiner configurations ideals: Containment and colouring
2021
Given a homogeneous ideal I&sube
Laparoscopic cholecystectomy in a patient with Steinert myotonic dystrophy. Case report.
2011
Myotonic dystrophy (MD) is a serious multi-systemic autosomal dominant disease. The estimated incidence is 1 in every 8000 births, with an estimated prevalence of between 2.1 and 14.3 cases per 100,000 inhabitants. Signs and symptoms vary from a severe form of congenital myopathy, present from birth and often fatal, to a classic form and a delayed form, which generally presents after the age of 50 and in which the only sign is a cataract and life expectancy is completely normal. We describe the clinical case of a 40-year-old woman with Steinert myotonic dystrophy who underwent laparoscopic cholecystectomy (under general anesthesia) for symptomatic gallbladder stones. The conduct of anesthes…
Steiner systems and configurations of points
2020
AbstractThe aim of this paper is to make a connection between design theory and algebraic geometry/commutative algebra. In particular, given any Steiner SystemS(t, n, v) we associate two ideals, in a suitable polynomial ring, defining a Steiner configuration of points and its Complement. We focus on the latter, studying its homological invariants, such as Hilbert Function and Betti numbers. We also study symbolic and regular powers associated to the ideal defining a Complement of a Steiner configuration of points, finding its Waldschmidt constant, regularity, bounds on its resurgence and asymptotic resurgence. We also compute the parameters of linear codes associated to any Steiner configur…
Using a TSP heuristic for routing order pickers in warehouses
2010
In this paper, we deal with the sequencing and routing problem of order pickers in conventional multi-parallel-aisle warehouse systems. For this NP-hard Steiner travelling salesman problem (TSP), exact algorithms only exist for warehouses with at most three cross aisles, while for other warehouse types literature provides a selection of dedicated construction heuristics. We evaluate to what extent reformulating and solving the problem as a classical TSP leads to performance improvements compared to existing dedicated heuristics. We report average savings in route distance of up to 47% when using the LKH (Lin-Kernighan-Helsgaun) TSP heuristic. Additionally, we examine if combining problem-sp…
The Random Neural Network Model for the On-line Multicast Problem
2005
In this paper we propose the adoption of the Random Neural Network Model for the solution of the dynamic version of the Steiner Tree Problem in Networks (SPN). The Random Neural Network (RNN) is adopted as a heuristic capable of improving solutions achieved by previously proposed dynamic algorithms. We adapt the RNN model in order to map the network characteristics during a multicast transmission. The proposed methodology is validated by means of extensive experiments.
An Efficient Distributed Algorithm for Generating Multicast Distribution Trees
2005
Multicast transmission may use network resources more efficiently than multiple point-to-point messages; however, creating optimal multicast trees (Steiner Tree Problem in Networks) is prohibitively expensive. For this reason, heuristic methods are generally employed. Conventional centralized Steiner heuristics provide effective solutions, but they are unpractical for large networks, since they require complete knowledge of the network topology. This paper proposes a distributed algorithm for the heuristic solution of the Steiner Tree Problem. The algorithm allows the construction of effective distribution trees using a coordination protocol among the network nodes. The algorithm has been i…